The microelectronic industry relies on a variety of different processes to manufacture microelectronic devices. Many processes involve a sequence of treatments in which different kinds of treatment fluids are caused to contact the workpiece in accordance with desired recipes. These fluids may be liquids, gases, or combinations thereof. In some treatments, solids may be suspended or dissolved in a liquid or entrained in a gas. It is highly desirable to capture and recover these treatment fluids for a variety of reasons including proper disposal, recycling, fume containment, process monitoring, process control, or other handling.
One capture technique involves using appropriately positioned ducts to capture treatment fluids. For instance, a typical manufacturing tool in the microelectronics industry involves supporting one or more workpieces in a processing chamber on a suitable support, such as a stationary platen, rotating turntable, or rotatable chuck. One or more ducts are positioned at least partially around the outer periphery of the support. As a treatment fluid is introduced into the processing chamber, an exhaust can be used to help pull the treatment fluid into the one or more ducts. With respect to rotating supports, centrifugal force causes fluids on a spinning workpiece and/or support surface to flow radially outward from the spin axis and into the duct(s).
Conventionally, a tool may include a single duct to capture different treatment fluids. However, using a single duct like this is not desirable in all instances. For example, some treatment fluids may be too reactive in the presence of other treatment materials. Other times, it may be desirable to capture different fluids using different capture conditions. Still other times, such as when recycling is desired, it may be desirable to capture a fluid in a dedicated duct to avoid contamination with other fluids.
Accordingly, tools containing multiple, stacked ducts, fixed relative to each other, have been used. Either the workpiece support and/or the stacked ducts themselves are raised and lowered in order to bring the appropriate duct into position. This conventional approach suffers from serious drawbacks. The stacked ducts make high-density tool packaging more difficult. The different ducts may also be subject to cross-contamination because they are always open to the workpiece and/or exhaust levels are not individually controlled. Some conventional duct systems also may not have the capability to separate the liquid and gas constituents of an exhaust stream. In some tools in which the duct structures themselves are moveable, drain and exhaust connections to external plumbing must also move, thereby adding undue complexity to tool design, manufacture, use, and service.
An innovative tool incorporating a flexible duct system is described in Assignee's co-pending U.S. Patent Publication No. US-2007/0022948-A1 (hereinafter referred to as the Co-Pending Application No. 1); as well as in Assignee's co-pending U.S. patent application Ser. No. 11/376,996, titled BARRIER STRUCTURE AND NOZZLE DEVICE FOR USE IN TOOLS USED TO PROCESS MICROELECTRONIC WORKPIECES WITH ONE OR MORE TREATMENT FLUIDS, in the names of Collins et al., filed Mar. 15, 2006, (hereinafter referred to as the Co-Pending Application No. 2). The entireties of these co-pending U.S. Patent Applications are incorporated herein by reference for all purposes. The “processing section 11” of the co-pending U.S. Patent Applications advantageously includes nested duct features that allow one or more duct pathways to be selectively opened and closed. For example, when the structures are moved apart relatively, a duct pathway opens and is enlarged between the structures. When the structures are moved together relatively, the duct between the structures is choked and is reduced in size. In preferred embodiments, multiple ducts can exist in the same volume of space depending upon how the moveable duct structures are positioned. Thus, multiple ducts can occupy a volume minimally larger than the volume occupied by only a single duct. The ducts are used to capture various treatment fluids, including liquid and/or gases, for recycling, discarding, or other handling. Different treatment fluids can be recovered in different, independent ducts to minimize cross-contamination and/or to use unique capture protocols for different fluids. Because of the nested character of the duct structures, the duct system also is extremely compact.
These co-pending U.S. Patent Applications also describe an innovative spray nozzle/barrier structure. This structure includes capabilities for dispensing treatment materials in multiple ways such as by a spray, a center dispense, and a showerhead. The barrier structure overlies the underlying workpiece. The lower surface of the barrier structure is shaped so that it defines a tapering flow channel over the workpiece. This approach offers many benefits. The tapering flow channel helps to promote radial flow outward from the center of the workpiece while minimizing recirculation zones. The taper also helps to smoothly converge and increase the velocity of flowing fluids approaching the outer edge of the workpiece. This helps to reduce liquid splash effects. The angle of the lower surface also helps liquid on the lower surface to drain toward the outer periphery. The tapering configuration also helps to reduce recirculation of particles back onto the workpiece. The configuration also helps facilitate chemical reclaim efficiency by better containment of fluids.
Notwithstanding all these benefits, further improvements are still desired. Firstly, during the course of treating a workpiece, the lower surface of the barrier structure may bear drops or films of liquid(s) used during the treatment. It would be desirable to find a way to effectively clean and/or dry the lower surface of the barrier structure quickly without an undue impact upon cycle time.
As another issue, it has been observed that the central region of workpieces tends to be processed to a lesser degree when treated with a spray bar that spans generally only a radius of the underlying workpiece. Yet, using a radius-spanning spray bar rather than a full diameter spray bar is desirable for ease of manufacturing or when a stream dispense is desired near the center of the workpiece. Thus, it would be desirable to improve the processing uniformity of radial spray bars.
Also the previously known barrier structure incorporates a spray bar mechanism as an integral member. The integrated component has a relatively large thermal mass. When heated materials are dispensed through the spray bar mechanism, the heat sink effect of the large thermal mass of the integrated components can cool the materials being dispensed and affect the temperature uniformity of the materials contacting the workpiece. This can impact the treatment performance in an undesirable way. Thus, there is a need to minimize this undesired thermal impact.
Additionally, there is an issue concerning mist containment in the process chamber. The center area of the barrier structure is generally open, even during a treatment. The center area allows air flow and functions much like a chimney through which plumbing components and the like are led to the dispensing components. During treatments, particularly spray treatments, some dispensed materials may have a tendency to escape upward through the chimney. It would be very desirable to contain the materials in the process chamber while still leaving an air flow path open.